Note 15 - Commitments and Contingencies (Details Textual) $ in Millions	6 Months Ended
Jun. 30, 2022 USD ($)
Sites Identified	359
Sites Subject of Actions Taken by US Government	30
Sites on Superfund National Priorities List	20
Personal Injury [Member]
Recorded Liability Related to Asserted Claims	94.00%
Recorded Liability Related to Unasserted Claims	6.00%
Personal Injury [Member] \| Minimum [Member]
Loss Contingency, Estimate of Possible Loss	$ 347
Personal Injury [Member] \| Maximum [Member]
Loss Contingency, Estimate of Possible Loss	$ 381

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=121557415&loc=d3e14557-108349

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124440162&loc=d3e12021-110248

Name:	us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant